     false
     (let [changes (map (comp math/abs -)
                        current-color previous-color)
-          channel-change-big-enough? #(< 0 100 %)]
+          channel-change-big-enough? #(< 50 %)]
       (some channel-change-big-enough? changes))))
+
+(defn color-with-alpha [c alpha]
+  (conj (vec (take 3 c)) alpha))
 
 (defn mosaic-color [current-color previous-color]
   (if (color-changed? current-color previous-color)
-    [255 0 0 255]
-    current-color))
+    current-color
+    (color-with-alpha current-color ALPHA-STILL)))
 
 (defn draw-mosaic
   [tri-points tri-glyphs drawn-mat

(def PIX-CNT1 (int (* DISPLAY-WIDTH DISPLAY-HEIGHT 4)))
(def PIX-CNT2 (int (* DISPLAY-WIDTH DISPLAY-HEIGHT)))

(def ALPHA-STILL 255.0)

;; 32 works
(def NUM-COL-BINS 32.0)
(def DISPLAY-BIN-SIZE (/ DISPLAY-WIDTH NUM-COL-BINS))
(def NUM-ROW-BINS (/ DISPLAY-HEIGHT DISPLAY-BIN-SIZE))



(defn draw [state]
  (let [{:keys [p-image frame-mat]} state]
    (q/background 255)
    (q/push-matrix)
    (q/translate DISPLAY-WIDTH 0)
    (q/scale -1 1)
